WHAT'S AT THE HEART OF MY CRYPTOGENIC STROKE? - A Patient Guide to Understanding Strokes of Unknown Cause
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WHAT’S AT
THE HEART OF MY
CRYPTOGENIC STROKE?
A Patient Guide to Understanding
Strokes of Unknown Cause
Supports the American Stroke
Association’s Cryptogenic Stroke Initiative.
1
Having a stroke of unknown cause, or cryptogenic stroke,
may be frustrating and overwhelming. In this guide, we will
provide you with information and resources that can help you
and your loved ones find answers around cryptogenic stroke.
With a proper diagnostic work-up and collaboration with
your physician, you can take part in finding the cause of your
stroke or other stroke risk factors and help prevent another
one from occurring.
2
CONTENTS
What is a Stroke?........................................................................ 4
What is a Cryptogenic Stroke?��������������������������������������������������� 4
Cryptogenic Stroke: What Does This Mean to Me?������������������� 5
Possible Causes of Your Stroke��������������������������������������������������� 5
After Your Stroke ������������������������������������������������������������������������ 7
Types of Heart Rhythm Monitoring ........................................... 9
Planning Your Discharge ����������������������������������������������������������11
Questions to Ask Your Doctor �������������������������������������������������� 12
Minimizing Your Risk of Another Stroke������������������������������������ 13
Being Prepared: Signs and Symptoms of a Stroke������������������ 15
ASA Stroke Resources ��������������������������������������������������������������� 16
References �������������������������������������������������������������������������������� 17
3
WHAT IS A STROKE?
Stroke, a disease that affects the blood flow of arteries leading to and within
the brain, is the No. 5 cause of death and a leading cause of disability in the
United States.1
Stroke is the No. 5 cause of death
A stroke occurs when a blood vessel that carries oxygen and nutrients to the
brain is blocked by a clot, or the vessel ruptures. When either of these events
happen, part of the brain cannot get the blood and oxygen it needs, and as a
result, brain cells subsequently die.
There are two types of strokes: hemorrhagic or ischemic. An ischemic stroke
occurs as a result of an obstruction within a blood vessel supplying blood
to the brain. It accounts for the significant majority of all stroke cases. A
hemorrhagic stroke occurs when a weakened blood vessel ruptures and spills
blood into brain tissue.
When brain cells die during a stroke, the abilities controlled by that area of the
brain are lost. These abilities may include speech, movement, and memory.
The way a stroke affects you depends on where the stroke occurs in the brain
and how much of the brain is damaged.
WHAT IS A CRYPTOGENIC STROKE?
In most cases, a stroke is caused by a blood clot that blocks the flow of
blood to the brain. In some instances, despite testing, the cause of a stroke
cannot be determined. In this case, the stroke of unknown cause is called a
“cryptogenic stroke.”
Your doctor may also refer to your cryptogenic stroke as an “embolic stroke of
unknown source” (ESUS). An embolic stroke is one caused by a blood clot that
starts somewhere other than the brain and breaks loose and travels through
the blood to the brain. About half of cryptogenic strokes are ESUS strokes.2
It’s estimated that about 1 in 3
ischemic strokes are cryptogenic.
It’s estimated that about 1 in 3 (35%) ischemic strokes are cryptogenic.2
Some studies suggest that the incidence of cryptogenic stroke is higher in
African-Americans (two times more likely) and Hispanics (46% more likely).3
4
CRYPTOGENIC STROKE:
WHAT DOES THIS MEAN TO ME?
Because approximately 1 in 4 stroke survivors will likely have another stroke,1
finding the cause of the stroke or risk factors that were previously unknown will
help your physician develop a plan personalized for you to prevent another
stroke. During your hospital stay and follow up care, you will want to discuss
with your physician the ways to best treat and prevent another stroke. Some
of these discussions may include diagnostic testing, blood work ups, and new
lifestyle changes.
Tip: Talk to your doctor to determine the best treatment plan for your stroke.
POSSIBLE CAUSES OF YOUR STROKE
• Atrial Fibrillation, also known as AF or AFib, is an irregular and often
very fast heart rhythm. About 5.2 million Americans are living with
AFib in the U.S.1 AFib occurs when the upper chambers of the heart,
or atria, beat rapidly and irregularly. This causes blood to pump
inefficiently to the rest of the body, which can cause symptoms like
heart palpitations, fatigue, and shortness of breath. When someone
has AFib, the blood is not moving through the heart the way it should
be, and blood clots can form within the left atria. A blood clot can
then travel out of the heart to the brain causing a stroke.
AFib increases the risk of stroke
more than five times.
AFib increases the risk of stroke more than five times,1
but often goes undetected since it can be asymptomatic and
may occur infrequently.
If your doctor thinks you may have AFib, they will order heart
monitoring to look for heart arrhythmias. If AFib is found, your
physician will most likely prescribe anti-clotting medications
(anticoagulants) that can help reduce your risk of another stroke.
To better understand whether you have AFib that can increase your
risk of having another stroke, be sure to ask your doctor about long-
term heart-rhythm monitoring.
5• Patent Foramen Ovale (PFO) is a hole in the heart that never closed
after birth. Patent foramen ovale is seen in about 25% of adults.4,5
During fetal development, this hole allows blood to circulate while
the lungs are still growing. Within a few months of birth, the hole
seals completely in about 75% of the population. When the hole
doesn’t close, the individual has PFO. For the vast majority of the
millions of people with a PFO, it is not a problem, even though blood
is leaking from the right atrium to the left. However, problems can
arise when that blood contains a blood clot, which can potentially
travel out of the heart to the brain and cause a stroke. PFO is present
in 40% of adults with cryptogenic stroke.4 Depending on your age, the
severity of your PFO or other factors, your physician may recommend
surgery to close the PFO.
• Hypercoagulable states or thrombophilic conditions are disorders
where a person’s blood has an increased tendency to form blood
clots. Blood clotting disorders can be either passed down from your
family or acquired during one’s lifetime. In one study, 1 in 7 stroke
patients tested positive for one of the inherited thrombophilias.6 Of
note, this condition is rare, but it can be dangerous.7 Thrombophilia
can be a cause of stroke — if the blood clots too quickly, then a
blood clot can form. If the clot travels to the brain and blocks off a
blood vessel, it can cause a stroke. Routine testing for the inherited
thrombophillias may not be done unless the cause of stroke is
unknown (especially in young persons), and a cause is being
investigated.
• Aortic Arch Atheroma is a build-up of fatty plaque within the aorta.
There are some people who develop fatty plaques (which contain
cholesterol and other substances from the blood) in a large artery
called the aorta. The aorta is an artery attached to the heart that
supplies a large amount of blood to the body. The specific part of the
aorta that comes off the heart is an area called the aortic arch — it is
the largest artery in the body. When a person develops fatty plaque
within the aortic arch, a piece of the plaque can loosen and float
into the blood. If this happens, the plaque can be circulated through
the blood to the brain, blocking a blood vessel which can cause a
stroke. Most people do not know when there is plaque build-up within
their aorta. A history of smoking, high blood pressure and high LDL
(bad) cholesterol, and diabetes makes people more likely to develop
plaque within a blood vessel, all of which are risk factors for both
stroke and heart disease.
6• Other potential causes of cryptogenic stroke are more rare and may
include cancer, infections (such as endocarditis, an infection of the
heart’s inner lining), and dissection (a tear in the wall of an artery).
Tip: A cryptogenic stroke can be caused by many different things. It’s
important to talk with your doctors to make sure that you or your loved one
are empowered with proper understanding of the possible cause.
AFTER YOUR STROKE
The American Stroke Association made recommendations in 2021 for what
is commonly called “the stroke work-up.” The stroke work-up includes tests
that should be conducted while the stroke patient is still hospitalized.
While some patients may continue to have the cause of their stroke
unknown, a cause or secondary stroke risk factors may be revealed with
further testing.
To properly determine the cause of your stroke and look for other
potential stroke risk factors, your doctor may conduct one or more of the
following tests as part of the stroke work-up:
• A brain Computed Tomography (brain CT) scan uses x-rays to take
clear, detailed pictures of your brain. A brain CT can show bleeding in
the brain or damage to brain cells from a stroke.
• Magnetic Resonance Imaging (MRI) uses magnets and radio waves
to create a picture of the organs and structures in your body. This test
can detect changes in brain tissue and damage to brain cells from a
stroke. An MRI may be used instead of, or in addition to, a CT scan to
diagnose a stroke or to provide more information about its cause.
• Blood tests that check for blood glucose levels, blood and platelet
counts, electrolyte levels and renal tests, and cardiac ischemia,
among other health factors.
• A blood glucose test measures the amount of glucose
(sugar) in your blood. Low blood glucose levels may cause
symptoms similar to those of a stroke.
• An A1C test measures your average blood glucose control
for the past two to three months.
7• A platelet count measures the number of platelets in your
blood. Blood platelets are cell fragments that help your
blood clot. Abnormal platelet levels may be a sign of a
bleeding disorder (not enough clotting) or a thrombotic
disorder (too much clotting).
• Activated Partial Thromboplastin Time (aPTT or APTT)
measures the time it takes your blood to clot.
• Prothrombin Time (PT) measures how long it takes blood
to clot. It also is used to check whether medicine to prevent
blood clots is working.
• International Normalized Ratio (INR) tests how well your
blood can form clots. Since a clot in the vessel of the brain is
a common cause of stroke, this test will help your physician
determine if you need anti-clotting medication.
• A fasting or non-fasting lipid profile is used to check your
cholesterol levels.
• Oxygen saturation – Your red blood cells carry oxygen through
your arteries to all of your internal organs. They must carry enough
oxygen to keep you alive. Normally, when red blood cells pass
through the lungs, 95-100% of them are loaded with oxygen. If you
have a medical condition, your oxygen saturation might be lower
than 95%. An oxygen saturation test is painless and is measured by
using a clip that fits on your finger.
• Heart rhythm monitoring may be administered in-hospital or at
home to help identify the cause of the stroke and guide stroke
prevention strategies. A heart rhythm device records heart rhythm
over both short and long periods of time. Heart rhythm monitoring
is ordered if your physician suspects AFib as a possible cause
or risk factor for having another stroke. The following 3 pages provide
more information on the types of heart rhythm monitoring.
• An echocardiogram (not to be confused with an electrocardiogram)
is a test that uses high frequency sound waves (ultrasound) to make
pictures of your heart. The test is also called echocardiography or
diagnostic cardiac ultrasound. This painless test can help to diagnose
PFO, endocarditis, heart valve problems, or other potential causes of
cryptogenic stroke. Transthoracic echocardiography (TTE) is the most
common type of echocardiogram.
8• Transesophageal echocardiography (TEE) is another test that
produces pictures of your heart using ultrasound. Unlike a standard
echocardiogram, the echo transducer that produces the sound
waves for TEE is attached to a thin tube that passes through your
mouth, down your throat and into your esophagus. TEE is used when
doctors need a more detailed picture of the heart than a standard
echocardiogram can give them.
TYPES OF HEART RHYTHM MONITORING
In all patients who have a suspected stroke, an electrocardiogram (ECG)
should be performed in the hospital to look for AFib or other cardiac conditions.
If you’ve had a cryptogenic stroke and an ECG or other external heart monitor
did not give your doctor enough information, American Heart Association
and American Stroke Association guidelines recommend an insertable heart
monitor or mobile outpatient telemetry to help determine if you have AFib.2,8
Your physician prescribes these diagnostic or treatment options. These devices
are not for everyone, but can be helpful in finding AFib in those who don’t have
symptoms or have infrequent episodes. Please talk to your doctor to see which
option is right for you.
Electrocardiogram (ECG) – A machine that records the heart’s electrical
activity. An ECG shows how fast the heart is beating and allows the
medical professional to verify if the heart rhythm is steady or irregular.
An ECG can help detect heart problems, such as AFib, or a previous heart
attack that may have led to a stroke. Typically, this is given in a hospital or
clinic setting. External patches are applied to the chest with wires connecting
to a large, portable ECG device.
9Mobile Continuous Outpatient Telemetry (MCOT) – An external
monitor that is worn for up to 30 days. The unit has wires attached to
the chest along with a unit (transponder) that is worn on the belt. This
device allows the patient to activate heart rhythm recording if he/she
experiences symptoms.
Tip: Follow your physician’s instructions during the heart monitoring process.
They will improve the chances of determining whether you have an irregular
heartbeat that could potentially cause another stroke.
Holter Monitor – An external heart monitor worn either in the hospital or at
home to help detect any heart rhythm abnormalities. During the 24-48 hour
monitoring period, the device records the heartbeat and rhythm. Typically, a
Holter device is a small unit (roughly the size of a deck of cards) that is secured
on a belt. Attached to the device are wires and patches that are placed on the
skin. A wireless Holter monitor may be worn up to several weeks.
10Insertable Cardiac Monitor (ICM, also sometimes called an implantable
loop recorder) – A small heart monitoring device that is placed just under
the skin, above the heart, during a minimally invasive procedure. The
ICM is about one-third the size of a AAA battery, and the latest devices
continuously monitor the heart for up to 4.5 years.
PLANNING YOUR DISCHARGE
Many stroke survivors are able to return home and resume many of the
activities they did before their stroke. However, some patients may need to
go to a rehabilitation or nursing center for assistance. Below are some tips
to help caregivers and patients prepare for discharge:
• Schedule an appointment with your primary care professional as
soon as possible, ideally within 1-3 weeks after discharge from the
hospital or inpatient rehabilitation.9
• Prepare a list of questions to take to the next doctor’s visit.
• Start a daily medication list. Include the drug name, purpose of
drug, dosage, possible side effects, and who prescribed each drug.
If you’re concerned about the drugs prescribed, ask the doctors to
work together to make sure that all drugs are taken appropriately.
Take this list with you to all doctor’s appointments.
• Consider mobility needs at home, including the need for adaptive
equipment to enable moving around more easily.
11QUESTIONS TO ASK YOUR DOCTOR
01 What caused my stroke?
02 What happens if the cause of my stroke is not identified?
03 Are there ways to determine the cause of my stroke or additional
factors that may put me at increased risk of having another stroke?
04 What tests or diagnostics can be done, such as long-term heart
rhythm monitoring, echocardiography, or genetic tests, to find the
cause of my stroke or additional risk factors that could cause
another stroke?
How is cryptogenic stroke treated?
05 (Treatment may vary per patient)
06 Is cryptogenic stroke typically hereditary?
For patients who received a home heart-monitoring device (either
07 insertable or external):
What is the purpose of my monitoring device?
How long can I wear it?
How will it impact my daily activities?
08 What can I do to minimize my risk of having another stroke?
What should I share with my primary care physician or neurologist
09 about my cryptogenic stroke once I am recovering at home?
Tip: Ask your health care providers to work together to help find the cause
of your stroke or other potential stroke risk factors. When cardiologists,
neurologists, primary care physicians and other health care professionals
work together, it ensures that you will receive the most thorough care and
interventions to help prevent another stroke and improve outcomes.
12MINIMIZING YOUR RISK OF ANOTHER STROKE
While the cause of your stroke may not yet be determined, it is important
to follow your physician’s medical advice and take your medications. If you
receive a heart monitoring device, you will also want to follow any heart
monitoring regimens prescribed. Additionally, you may reduce your risk
factors for stroke by following a healthy lifestyle. Here are seven behaviors the
American Heart Association has identified, called Life’s Simple 7®, to help you
minimize the risk of another stroke.
1. Manage Blood Pressure
High blood pressure is a major risk factor for heart disease
and stroke. When your blood pressure stays within healthy
ranges, you reduce the strain on your heart, arteries,
and kidneys, which helps keep you healthier longer. You
can manage high blood pressure by taking prescribed
medication from your physician and managing your
sodium.
2. Control Cholesterol
High cholesterol contributes to the development of fatty
plaque, which can clog arteries and lead to heart disease
and stroke. When you control your cholesterol, you are
reducing potential plaque and blockages that could occur.
3. Reduce Blood Sugar
Most of the food we eat is turned into glucose (or blood
sugar) that our bodies use for energy. When your body
does not process glucose properly and your blood sugar
is too high, diabetes can develop. Over time, diabetes can
cause damage to your heart, kidneys, eyes, and nerves.
Healthy eating is key to managing blood sugar levels.
4. Get Active
Living an active life is one of the most rewarding gifts you
can give yourself and those you love. Simply put, daily
physical activity increases the length and quality of your
life. Stroke survivors are encouraged to exercise or be active
at least 10 minutes, 4 times a week or have more vigorous
activity for a least 20 minutes, twice a week. Stroke
survivors who tend to sit for long periods of time or are not
able to exercise by themselves are encouraged to find help
exercising in a safe manner. Your doctor may recommend
a formal program that can help with making, and keeping,
needed lifestyle changes.2
135. Eat Better
A healthy diet is one of your best weapons for fighting
cardiovascular disease. When you focus on heart healthy
meals and snacks, you improve your chances for feeling
good and staying healthy – for life!
6. Lose Weight
When you shed extra fat and unnecessary pounds, you
reduce the burden on your heart, lungs, blood vessels, and
more. An active lifestyle can help, lowering your blood
pressure, cholesterol, and blood sugar and elevating your
mood as well.
7. Stop Smoking
Cigarette smokers have a higher risk of developing
cardiovascular disease. If you smoke, quitting is the best
thing you can do for your health.
Learn more about Life’s Simple 7® at heart.org/mylifecheck
Tip: Most recurrent strokes can be prevented. Taking steps to manage the
cause of your stroke can reduce the risk of another event.
14BEING PREPARED: SIGNS AND SYMPTOMS
OF A STROKE
Once you have had a stroke, you are at a greater risk for another stroke.
F.A.S.T. is an easy way to remember the sudden signs of stroke. Learning the
signs and symptoms of strokes and getting to a hospital quickly will give you
the best chance of having a positive outcome after a stroke. When you spot
the signs, you’ll know when you need to call 911 for help. F.A.S.T. stands for:
F
Face Drooping
Does one side of the face droop or does it feel numb?
Ask the person to smile. Is the person’s smile uneven?
A
Arm Weakness
Is one arm weak or numb? Ask the person to raise
both arms. Does one arm drift downward?
Speech Difficulty
S Is speech slurred? Is the person unable to speak
or hard to understand? Ask the person to repeat a
simple sentence, like “The sky is blue.” Is the sentence
repeated correctly?
T
Time to call 911
If someone shows any of these symptoms, even if the
symptoms go away, call 911 and get the person to
the hospital immediately. Check the time so you’ll
know when the first symptoms appeared.
It is important to have a conversation with your friends and family so they are
aware of the signs and symptoms of stroke. Getting the family involved and
ready to respond can make a big difference if another stroke occurs.
To learn other potential signs of a stroke, go to: stroke.org/warningsigns.
15ASA STROKE RESOURCES
• Call 1-888-4-STROKE (1-888-478-7653) or visit us at:
stroke.org/unknownstroke to learn more about cryptogenic stroke.
• Find a list of local support groups at stroke.org/strokegroup.
• The American Stroke Association Support Network is dedicated to
patients and their caregivers, family, and friends. The Support Network
provides a place for patients, families, and caregivers to give and receive
support, improve their own health, and impact the lives of others. To
learn more and register for free, go to: stroke.org/supportnetwork.
• Call the American Stroke Association’s “Warmline” at 1-888-4-STROKE
(1-888-478-7653) to speak with others who have similar stroke
experiences. Join our facebook.com/americanstroke &
twitter.com/american_stroke communities.
• Sign up for Stroke Connection, a free monthly e-newsletter for stroke
survivors and caregivers: strokeconnection.org.
• Visit stroke.org.
16REFERENCES
1. Virani SS, Alonso A, Aparicio HJ, et al. On behalf of the American
Heart Association Council on Epidemiology and Prevention Statistics
Committee and Stroke Statistics Subcommittee. Heart disease and stroke
statistics-2021 update: a report from the American Heart Association.
Circulation. 2021;143:e00–e00.
2. Kleindorfer DO, Towfighi A, Chaturvedi S, et al. 2021 Guideline for the
Prevention of Stroke in Patients with Stroke and Transient Ischemic Attack:
A Guideline from the American Heart Association/American Stroke
Association. Stroke. 2021;52:e364–e467.
3. Yaghi S, Bernstein RA, Passman R, et al. Cryptogenic Stroke Research and
Practice. Circulation Research. 2017;120:527–540.
4. Mojadidi MK, Zaman MO, Elgendy IY, et al. Cryptogenic Stroke and Patent
Foramen Ovale. J Am Coll Cardiol. 2018;71:1035-1043.
5. Purvis JA, Morgan DR, Hughes SM. Prevalence of patent foramen ovale in a
consecutive cohort of 261 patients undergoing routine “coronary” 64-multi-
detector cardiac computed tomography. Ulster Med J. 2011;80(2):72-75.
6. Hankey GJ, Eikelboom JW, van Bockxmeer FM, et al. Inherited
Thrombophilia in Ischemic Stroke and Its Pathogenic Subtypes. Stroke.
2001;32:1793-1799.
7. Khan S and Dickerman JD. Hereditary thrombophilia. Thrombosis J.
2006;4:15.
8. January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS focused update
of the 2014 AHA/ACC/HRS guideline for the management of patients with
atrial fibrillation: a report of the American College of Cardiology/American
Heart Association Task Force on Clinical Practice Guidelines and the Heart
Rhythm Society. Circulation. 2019;139.
9. Kernan WN, Viera AJ, Billinger SA, et al. Primary Care of Adult Patients
After Stroke: A Scientific Statement from the American Heart Association/
American Stroke Association. Stroke. 2021;52:e1-e14.
17NOTES 18
NOTES
19stroke.org/unknownstroke Supports the American Stroke Association’s Cryptogenic Stroke Initiative. © Copyright 2021 American Heart Association, Inc., a 501(c)(3) not-for-profit. All rights reserved. American Stroke Association is a registered trademark of the AHA. Unauthorized use prohibited. DS18144 8/21
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